The VDD regulator used to be enabled only at tegra_output_hdmi_enable,
which is called after a sink is detected. However, the HDMI hotplug pin
works by returning the voltage supplied by the VDD pin, so this meant
that the hotplug pin was never asserted and the sink was not detected
unless the VDD regulator was set to be always on.

This patch moves the enable to the tegra_hdmi_init() function to make
sure the regulator will get enabled and therefore ensure proper hotplug
detection.
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>